Apparatus for bore hole drilling and logging



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Jan. 22, l1963 United -States Patent O 3,074,493 APPARATUS FOR BORE HOLEDRILLING AND LOGGING John D. Bennett, Richardson, Tex., assigner to SunOil Company, Philadelphia, Pa., a corporation of New Jersey Filed Nov.4, 1957, Ser. No. 694,256 6 Claims. (Cl. 175-107) rl`his inventionrelates to apparatus for bore hole drilling and logging and, moreparticularly, to the modification of a turbodrill assembly to permit theprojection of a logging assembly below the bit thereof.

Conventional methods of well logging, whether of electrical or othertypes, involve the absence of the drill stem during the loggingoperation. This has two serious drawbacks in that not only must specialtime be consumed in running the well log, during which time the drillstem must be out of the hole, but after a period of drilling, due to thefact that the drill stem must be removed, there is inevitably a delaybefore the new part of the hole may be logged, during which delay thereoccurs invasion of the formation by drilling liquid. Since the drillingliquid has physical properties of its own, it may,

by penetration of porous layers, greatly change theirv properties so asto interfere with their detection. For example, in the case ofelectrical logging, the conductivity of the liquid will effect changesin the apparent conductivity of the formations; and in the case ofacoustic logging the absorption and Velocity of sound will be changed,etc.

Proposals have been made to effect electrical logging by using the drillbit or one or more other parts of the drill stem as logging electrodes.In line with this it has been proposed to supply special drill stemtubing containing one or more conductors which are electricallyconnected in the assembly of the drill stem and extend tovrecordingapparatus at the surface. rIhe use of such an arrangement has been foundto be impractical because of high cost and wear. l

; Proposals have also been made to support one or more electrodes onwire lines to be dropped below a core bit into the lower portion of ahole from which the bit has been raised. This procedure has also provedimpractical inasmuch as special handling has been required at thesurface, but particularly because core bits are not generally desiredfor the major drilling activities but are used only for specialpurposes.

In the applications of Mayes and Jones, Serial No. 683,027, filedSeptember l0, 1957, and of Bennett, Chaney, Jones and Mayes, Serial No.685,717, filed September 23, 1957, there are disclosed methods andapparatus for logging below a drilling bit which methods and apparatusavoid the shortcomings referred to above. In accordance with thedisclosure f said applications, the logging methods and apparatus may beused when a drill string is in a bore hole and may be used at any timewith a minimum of interruption of drilling. Not only may the logging beaccomplished just prior to removal of the drill string for the purposeof changing a bit, but the logging may be carried out to Ibe promptlyfollowed by a continuation of drilling. In brief, a self-containedenergizing and recording apparatus may be dropped through a drill stringin go-devil fashion or may be pumped down therethrough when the drillstring has been lifted to only a limited extent from the bottom of thehole to provide a region for reception of an electrode or other loggingassembly. The apparatus particualrly includes an assembly of a typesuitable to pass through the mud flow openings of a jet bit. These jetopenings are generally at relatively small angles with respect to the4drill stem axis 3,@74A93 Patented Jan. 22, 1963 ICC and a flexibleassembly may, accordingly, be projected therethrough to extend beneaththe bit. For electrical logging the assembly is an electrode assembly;for acoustic or other logging it may be of suitable type for exposure tothe walls of the hole.

The self-contained assembly which is lowered to the vicinity of the bitcontains, for electrical logging, not only means for supplying currentto the earth, but also means for recording various potentials at theelectrodes of the assembly, the recording being desirably, and asdisclosed in said prior applications, effected magnetically.

There has recently come into use a new type of bore hole drill known asa turbodrill involving a turbine rotor connected to a drill bit, therotor being driven by the drilling fluid. This requires diversion of thefluid from the axis for the -driving of the tur-bine blading andtortuous passages through the blading so that a logging element cannotbe passed therethrough to project below the bit. The full flow ofdrilling fluid must be directed through the turbine and this preventsthe use of a central passage through which a logging element might bedirected.

It is the general object of the present invention to provide a drillingarrangement through which there is provided a straight or substantiallystraight passage through which the logging element, for example, atubular elongated member carrying electrodes, may be passed so as toproject beyond a bit during a logging operation. Provision is made inaccordance with the invention, to close off this passage to prevent suchfree flow of drilling uid as would interfere with proper operation ofthe turbine.

The foregoing general object of the invention as well as `othersparticularly relating to details of construction and operation willbecome apparent from the following description, read in conjunction withthe accompanying drawing, in which:

FIGURE 1 is a vertical section showing one form of turbodrill assemblywhich may be provided in accordance with the invention; and

FIGURE 2 is a fragmentary section showing another valve arrangementwhich may be used.

The logging assembly, per se, forms no part of the present invention andis indicated merely diagrammatically as will more fully appearhereafter. It may be of the form disclosed in `detail in the foregoingapplications, consisting of a pressure-tight housing in which is locatedrecording apparatus assembled with a wand which is adapted to projectbeyond the bit. For consistency of description, the apparatus will bereferred to in the form of an electrical logging apparatus in which thewand carries electrodes arranged for the introduction of alternatingcurrent into the earth and for pick up of alternating and directpotentials. It will be understood, however, that other logging apparatusmay be employed in which a pick up or energizing element is of elongatedtype and of sufficiently small `diameter to pass through passages suchas are hereafter described. The term wand has been particularly appliedin the applications referred to above because it is flexible but hasconsiderable stiffness to enable it to deflect from a straight conditionto pass through the non-axial openings of jet bits. As will appear, inthe present case, if the bit is provided with an axial passage the wandmay be quite rigid, though because of the length which it. will normallyhave and its relatively small diameter it will be somewhat flexible.Flexibility, however, is not then a requirement. However, if the bit hasonly diverging, non-axial, mud passages, the wand may be more llexibleas described in said prior applications. For consistency of descriptionand reference to said prior applications the term wand will be used todescribe the element which carries electrodes or other energizing orpick up apparatus, whether exibility is or is not an importantcharacteristic.

Referring first to FIGURE l, there is shown therein an assembly, which,except for rather minor changes, is a conventional turbodrill. A housingmember 2, which is arranged to be secured in conventional fashion to thelower end of a hollow drill stem through which mud is pumped as thedrilling fluid, encloses and mounts the turbine, the circulated mudentering its neck 4 through passage o and being delivered by a sidepassage 8 to the turbine. The turbine shaft, indicated at 10, isprovided with a suitable extension at l2 to carry the bit 14 which maybe of any conventional rotary type and is indicated as of the multiplecone rock type provided with jet openings 16. In such case, guidingmeans 17 are provided for causing the wand to pass through one of thejet openings as described in said Mayes and Jones application. However,if a bit is used which has a central opening, special guiding means neednot be provided, the wand then remaining centrally located.

The bearing arrangement for the turbine shaft is conventional andindicated at 18, comprising rotating and fixed rings lubricated by thedrilling fluid and provided with by-pass means to guide the drilling uidto the blading 2t? of the turbine, the blading comprising rotary vanescarried by a hub forming part of the shaft and stationary redirectingvanes carried by the housing member Z. After passage through the bladingthe fluid ows through passages 24 to a central axial passage 26 andthence to the bit for ow through the jet or other openings therein. Aconventional lower bearing arrangement is indicated at 22.

For proper operation of the turbine, the tail passage 26 must beisolated from the entrance region of the uid above the turbine, andhence conventionally there is not provided an axial passage which, inthe present instance, is provided at Z8.

In order to close the passage 28 during drilling, the upper end of theturbine shaft is provided with a cylindrical socket 40 within whichthere is located the rubber valve 46 which is normally closed at 48,being retained in position by the snap ring 56. Differential mudpressure across the valve by compression of the valve normally maintainsits opening in closed condition, but a wand may readily penetrateenlarging the opening for its passage.

A converging-diverging diffuser passage 54 is provided in the neck Il bymeans of a metal ring 52 to provide a central guide for the wand tocause it to penetrate the valve 46 centrally.

The logging wand 56 may be of the type disclosed in said priorapplications, and may be provided, as described therein, primarily by acoiled spring carrying, additionally, electrodes such as S and 60 in thecase of electrical logging apparatus, the wand being otherwiseexternally insulated. The wand is carried by the lower end of thehousing 62 within which there is located the currentproviding andrecording apparatus of the type disclosed in said prior applications, orof some other type if the logging is other than electrical. lf acontinuous axial passage is provided running through the bit, the wandmay be essentially rigid, except for the possibility of ilexure due toits considerable length which may ordinarily be upwards of twenty feet.

Drilling may be effected in conventional fashion with the drill in thebottom of the hole, mud flow being provided to drive the turbine andthereby rotate the bit.

When it is desired to effect logging, the bit will be raised a suitabledistance above the bottom of the hole, and the logging apparatus maythen be dropped or lowered through the drill stem and the wand will passthrough the guide opening at Sd and then penetrate the valve at 46,passing thence downwardly through the passages 28 and 26 and beingguided through the jet opening 16 after deflection by the guiding means17. h1 this operation it will ordinarily engage the wall of the hole andwill be deflected thereby downwardly to extend along the hole, though,of course, it will pass downwardly centrally if the bit is provided witha central opening. The housing 62 may be brought to rest in any suitablefashion, and there may be used a cushioning arrangement such as shown insaid prior applications to prevent damage by impact. After the loggingapparatus is thus located in position, the drill stern may be raised andlogging effected as described in said prior applications, there beingnoted the corresponding times and depths so that the record made withinthe housing 62 may be ultimately related to depth. Following completionof the logging operation, the logging apparatus may .be pulled up by asupporting wire line, if it has been lowered thereby, may be retrievedby an overshot it has been dropped or pumped down, or may be left withinthe drill stern if immediately following the logging the drill stem isto be withdrawn for changing of the bit.

It will be apparent from the foregoing that the apparatus which has beendescribed consistently provides for both operation of the turbodrill andfor logging by means of a device which is to be projected through thebit.

reference may now be made to an alternative valve arrangement which maybe used at the upper end of the turbine shaft. In this case, the shaftwhich is indicated at 84 is provided with a socket 86 arranged toreceive a valve 88 which may be made of natural or synthetic rubber andwhich is molded to provide a stem portion 92 which is constricted a-sindicated at 94 to close off the opening therethrough, the portion ofthe extension 92 above the constriction being flared as indicated at 96.The valve is secured in position by a snap ring gt). Above this there isthe convergent wand guiding member 98 which may be of the same type asat 52 and which will insure a central position of the lower end of thewand to cause it to enter properly the valve 88 and the central openingtherebeneath. The valve arrangement is such that it is normally closedat the constriction 94 and is held tightly closed by reason of thedifferential mud pressure existing between its exterior and interior.When logging is to be effected, the wand will enter the opening providedby the flared portion of the valve at 96 and the thrust due to thelogging apparatus will cause it to open and pass through the valve andinto the central opening in the shaft, the wand thereafter passingdownwardly in the fashion already described. To insure normal closure ofthe valve there may be molded into it a metal ring provided with springfingers 97 tending to move inwardly. These tingers will flex outwardlyto permit the wand to pass. The exterior of the valve may also be shapedso that pressure thereagainst due to mud ow will counteract any tendencyfor opening provided by impact of mud into the daring mouth of thevalve.

It will be evident from the foregoing that other variations of valveconstruction may be adopted, all for the purpose of providing a freedirect passage for the wand while preventing by-pass of the blading ofthe turbine. The invention is accordingly not to be regarded as limitedexcept as required by the following claims.

What is claimed is:

1. A drill assembly of the type arranged for connection to the lower endof a hollow drill stem, said assembly comprising a bit, means controlledby fluid owing downwardly through a drill stem to which the assembly maybe connected for producing drilling movements of the bit, said meansbeing provided with fluid passages for its operation arranged to receivefluid from a drill stem and of a non-straight type preventing directpassage therethrough of a logging means adapted to operate by projectionbeyond said bit, said first mentioned means being provided with apassage auxiliary to the first mentioned passage through which suchlogging means may pass, said auxiliary passage being such that, unlessclosed,

it would receive Huid from a drill stem, and means closing saidauxiliary passage during drilling to restrict downward flow of uidtherethrough but arranged to be opened for downward passage of saidlogging means for a logging operation.

2. An assembly according to claim 1 in which said means controlled bylluid owing through a drill stem comprises a turbine for rotating thebit.

3. An assembly according to claim 2 in which said auxiliary passage isthrough a shaft of said turbine.

4. An assembly according to claim 1 in which the means closing saidauxiliary passage comprises a normally closed valve means of yieldingmaterial restrict` ing downward uid flow and arranged to be opened bydownward insertion of said logging means therethrough.

5. An assembly according to claim 2 in which the means closing saidauxiliary passage comprises a normally closed valve means of yieldingmaterial restricting downward uid ow and arranged to be opened bydownward insertion of said logging means therethrough.

6. An assembly according to claim 3 in which the means closing saidauxiliary passage comprises a normally closed valve means of yieldingmaterial restricting downward fluid ilow and arranged to be opened bydownward insertion of said logging means therethrough.

References Cited in the le of this patent UNITED STATES PATENTS 460,369Canan Sept. 29, 1891 1,482,702 Scharpenburg Feb. 5, 1924 1,727,276 DiehlSept. 3, 1929 2,070,912 McDermott Feb. 16, 1937 2,114,583 Adams Apr. 19,1938 2,254,641 Bannister Sept. 2, 1941 2,585,286 Tubbs Feb. 12, 19522,724,442 Mundt Nov. 22, 1955 2,890,859 Garrison June 16, 1959

1. A DRILL ASSEMBLY OF THE TYPE ARRANGED FOR CONNECTION TO THE LOWER ENDOF A HOLLOW DRILL STEM, SAID ASSEMBLY COMPRISING A BIT, MEANS CONTROLLEDBY FLUID FLOWING DOWNWARDLY THROUGH A DRILL STEM TO WHICH THE ASSEMBLYMAY BE CONNECTED FOR PRODUCING DRILLING MOVEMENTS OF THE BIT, SAID MEANSBEING PROVIDED WITH FLUID PASSAGES FOR ITS OPERATION ARRANGED TO RECEIVEFLUID FROM A DRILL STEM AND OF A NON-STRAIGHT TYPE PREVENTING DIRECTPASSAGE THERETHROUGH OF A LOGGING MEANS ADAPTED TO OPERATE BY PROJECTIONBEYOND SAID BIT, SAID FIRST MENTIONED MEANS BEING PROVIDED WITH APASSAGE AUXILIARY TO THE FIRST MENTIONED PASSAGE THROUGH WHICH SUCHLOGGING MEANS MAY